The present invention pertains generally to mobile equipment for the forming of and removal of earthen material from a ground hole by a pressurized water flow and suction.
In the uncovering of buried utilities great care should be exerted to avoid contacting the buried utility article with mechanical digging means. Present practice is to remove earthen material, when in the proximity of the buried article, by manual digging which is both time consuming and hence costly. The use of a backhoe machine or drilling equipment encounters the risk of damage to the buried utility article as contact with a pipeline, an electrical cable or fiber optic telephone cable most likely results in damage and costly repair of the utility item. In some cases such contact presents a risk to the equipment operator.
Additionally, the use of mechanical digging equipment is also inefficient as such equipment necessitates transport to and from the digging site. Mechanical digging equipment is also impractical from the standpoint that when only verification of utility depth is necessary by a utility contractor, such can be done by the forming of a relatively small diameter ground hole not possible with commonly used mechanical digging equipment.
U.S. Pat. No. 5,016,717 is of interest in that it discloses a mobile digging apparatus using pressurized water and suction. No provision is made for reuse of water hence a convenient water source is necessary which is not always the case. Further, the excavated dirt and water are collected in a tank which requires periodic dumping resulting in a dumping problem as various governmental prohibitions exist against such dumping at all but approved sites. In certain areas of the United States water shortages exist making the one time use of water to dislodge earthen material impractical from a water conservation standpoint. The transport of a water supply tank and a second or collection tank for water and earthen material is such as to require a vehicle of considerable size and weight to hinder maneuvering in all but large, well surfaced areas.